SAILPLANES

196R-2OOOJ J^s^a, - , Wing profiles 1965 - 2000

(Profiles shown in the previous volume , Sailplanes 1945 - 65, are not all reproduced here

Kaiser Ka -13 Co 535/549 blend

Culver Woodstock root profile

Wortmann FX 62 - K -131 (Thickened to 14.4%)

Wortmann FX 62 - K -153

Eppler E 662 Wortmann FX 66 -17 All -182

Wortmann FX 76 MPA -160 (Sunseeker) Delft DU 80 -141 Wortmann FX 79 - K -144/17 (FX6o-i26mod)_

Delft DU 80-176 (FX6i -i63Mod>

Delft DU 84 -132 V2

Horstmann - Quast HQ -10/16.42 Delft DU 84-158

Delft DU 89 -134/14 Horstmann - Quast HQ -17/14.38 Delft DU 89 - 138/14

Horstmann - Quast HQ - 35

AH 81-131

Horstmann Quast HQ -144 - 39 W3 (For Wortmann flap)

Horstmann - Quast - Althaus HX - 83 - Nase 80

XX79/18N2

HQ Discus 2 Root HQR 1 (ETA) (From photo)

HQ Discus 2 Tip (From photo) Martin Simons

Sailplanes 1965 - 2OOO

To Jean, my dear wife, who has tolerated, crewed for and supported this crazy glider pilot for fifty years

£QIP CONTENTS

4 Preface 51 Darmstadt 111 Glasflugel 5 Introduction 51 D 37 111 H-201 Standard Libelle 51 D 4o 113 H-401 Kestrel The Sailplanes 52 041 115 Glasflugel 604 Kestrel 22 117 H-205 Club Libelle 13 AUSTRALIA 52 Munchen 119 H-206 Hornet 13 Schneider ES - 65 Platypus 54 Mu-28 121 H - 303 Mosquito 15 Sunderland Moba - 2 123 Glasflugel 304 56 Stuttgart 16 BRAZIL 58 FS - 25 Cuervo 125 Rolladen - Schneider 16 Barros CB-2 Minuano 58 FS - 29 125 LS-i 18 Widmaier/IPE - KW-i 127 LS-2 Quero Quero 60 Alexander Schleicher GmbH 129 LS-3 20 WidmaierKW-2Bigua 60 ASW 12 131 LS-4 62 ASK 13 132 LS-6 20 BRITAIN 62 ASK 14 134 LS-y 21 Sigma 65 ASW 15 136 LS-8 67 ASW 17 24 Slingsby Sailplanes Ltd 71 ASK 18 138 Scheibe Flugzeugbau 24 SlingbsyT-5i DartiyR 71 ASW 19 140 SF-27M 27 Slingsby T - 53 Phoenix 73 ASW 20 29 Slingsby T-65 Vega 77 ASK 21 141 Schempp-Hirth GmbH 77 ASW 22 141 Cirrus 30 CZECH REPUBLIC 81 ASK 23 143 Holighaus Nimbus i 30 LET L-23 Super Blanik 81 ASW 24 147 Standard Cirrus 32 VSO-io 85 ASH 25 148 Nimbus 2 87 ASH 26 152 Janus 34 FINLAND 89 ASW 27 154 Mini Nimbus 34 PIK-20 90 ASW 28 154 Ventus A, B und C 158 Nimbus 3 36 FRANCE 90 Burkhardt Grob 160 Discus 37 Centrair C- 101 Pegase Flugzeugbau GmbH 162 Duo Discus 37 Centrair C - 201 Marianne 90 C- 102 Astir CS &.G- iO2Club 164 Ventus 2A, 26, & 2C 39 Wassmer WA-26 Squale und 94 G- 1 03 Twin Astir &G-iO3Twin2 166 Nimbus 4 &4DM WA-28Espadon 97 G- 104 Speed Astir 169 Discus 2

41 GERMANY 97 ETA 171 Siebert Sportflugzeugbau 41 The Akafliegs 171 Sie-3 100 Glaser - Dirks and DG 41 Braunschweig Flugzeugbau GmbH 173 Start und Flug 43 SB-8 und SB-8 V2 100 DG-100&DG-101 173 H-ioiSalto 43 SB - 9 102 DG -200, 202- 17 £ DG -400 45 SB-10 104 DG-300 175 Stemme GmbH £ Co KG 47 SB-11 107 DG-500 175 Stemme S - 10 Chrysalis 49 SB-i3Arcus 108 DG-6oo 108 DG-8oo 177 HUNGARY 227 USA 177 KM - 400 229 Applebay Aero - Tek Zuni

179 ITALY 232 Bryan Aircraft Company 181 Caproni Calif A- 21$ 234 Schreder HP-14 181 M -300 234 SchrederHP-i8

183 JAPAN 238 BJ -ib Duster 183 LAD Mita - 3 Kai - i 185 LADSS-2 240 Concept 70 185 Takatori SH - 15 240 Laister LP 49 & Nugget 187 LITHUNIA 187 LAK-iyA 241 Marske 241 Marske Pioneer 189 POLAND 243 Markse Monarch PW - 5 Smyk 191 EQIP Werbung & Verlag GmbH 195 PZL KR - 03 Puchatek 245 Project Genesis Hauptstrasse 276 195 Swift S - 1 0-53639 Konigswinter MDM Fox 248 Schweizer Aircraft Corporation Germany 197 Telephone: +49.2223.917070 SGS1-26E 198 SZD-30&30C Pirat 248 Telefax: +49.2223.917010 198 SZD - 32 Foka 5 250 SGS2-33 Website: www.eqip.de 201 SZD - 36 & 39 Cobra 15 & 17 252 SGS i - 34 Email: [email protected] © Martin Simons 2004 203 SZD - 43 Orion 254 SGSi-35 204 SZD-38Jantari 256 SGS i - 36 Sprite 206 SZD - 41 Jantar Standard 256 SGM2-37 The right of Martin Simons to 206 SZD -42 Jantar 2 be identified as the author of this work has been asserted by SZD - 48 Jantar Standard 2 256 Sunseeker 209 him in accordance with the 209 SZD - 48/3 Jantar Standard 3 Copyright, Design and Patents 211 SZD - 50 Puchacz 263 Woodstock Right Act of 1988. 211 SZD -51 Junior All rights preserved. No part of SZD -55 /i 213 this book may be reproduced or 215 SZD -56 Diana 263 APPENDICES transmitted in any form or by any means, electronic or me­ ROMANIA 262 How a High-Performance chanical. Including photocopy­ 217 ing, recording or by any informa­ 217 ICAIS-28B2 Sailplane is Manufactured tion storage and retrival system, 219 ICAIS-29 (Karl-Friedrich Weber DC without the permission from the Flugzeugbau) publisher in writing. 221 SWITZERLAND 221 FFC Diamant 269 Bibliography Printed in Czech Republic by 223 Neukom Elfe S - 2 & S - 3 269 Index Graspo CZ, a.s. Zlin 225 Neukom Elfe S - 4 271 Index of Names ISBN 3-9808838-1-7 227 Pilatus 6-4 272 Errata and Notes Cover: Thorsten Fridlizius, Nimbus 40 in New Zealand PREFACE

The nine year old boy who, in 1939, had gazed in fascination at attended the next meeting, at the Wasserkuppe in 1974. Since then wooden sailplanes with translucent wings, and who as a teenager the international Vintage Glider Club has flourished and expanded. had hopped and crashed a Dagling, by 1967 had entered a soaring The need to trace and record the whole development from the start competition and done quite well. A Gold C distance flight in a Ka 6E of the sport in 1920, was pressing. These books are the result. This was achieved from Dunstable northwards to Bishop Auckland. Sever­ volume, following directly from the previous two, brings the story al failures to complete the 300 km triangle in England followed. Two forward from 1965 to the end of the century. years of spare time were spent rebuilding and modifying a Skylark 2. Again, it has not been possible to include all the types of sailplane We moved to Australia in 1968. My family say this was because con­ that appeared during the period. A preliminary list for this volume ditions there were better for soaring. There was some truth in this. included more than three hundred. Cutting was inescapable. In ret­ Two jobs were offered. Whichever I chose would mean a change of rospect it is easy to see now that the main stream has been the de­ professional direction as well as domicile. The post in Adelaide was velopment of plastic composite sailplanes in Europe, particularly taken because of the prospect of soaring over the Murray River Germany and Poland. Revolutionary when they first appeared, plains that stretch for a thousand kilometres east of the Mount these now have become orthodox. At the beginning it was not at all Lofty and Flinders Ranges. clear that this was to be the future. There was a long period of trial Before leaving England I spent some time wondering whether we and experiment, a proliferation of ideas, proposals, new ventures, should take a sailplane. Glass-fibre-reinforced plastic (GRP) discoveries, new instruments, new techniques. sailplanes were beginning to arrive in England. I spent an hour Some experimental sailplanes were never produced in numbers studying one. It was impressive and expensive. I postponed any de­ but were highly influential, pointing the way ahead. Others indicat­ cision but soon after arriving at the Waikerie Gliding Club I found ed only where future developments had better not go. Sailplanes myself enjoying the delightful GRP Glasfliigel Libelle H - 301. The were produced in many countries and all deserve their place in the advance in performance was amazing. Soon afterwards I imported a record. Some were and are still being built in wood, metal and other Kestrel 17. Here were new complexities. As well as the familiar sim­ materials. Many of these are highly interesting and original. It was ple controls and basic instruments, with electronic audio variome­ felt that they should be described where possible, if only for the sake ter and climb averager, there was multi-channel radio, oxygen gear, of variety. As many as possible have been included. Details of what a retracting undercarriage, camber flaps with combined landing was done have often been lost, or, in several cases, buried in dark flap, a tail parachute brake, water ballast. cellars or dusty archives where no-one is prepared to search. The fi­ In the following years, other modern sailplanes were owned and nal selection, as before, has depended on the availability of records flown with occasional contest successes. I achieved a State Champi­ and drawings but also reflects some personal bias and preference. onship once and broke the British National speed record for the 300 km triangle. (John Delafield took it in South Africa within a Where do we go from here? few days.) I never had the consistency required for major competi­ tion wins but one day at the Australian Nationals in 1971 I beat the It is not easy to see how development will continue from the year visiting world champion, Helmut Reichmann, in a race round a 428 2000 onwards. Among the newest sailplanes, some are huge and km triangle. The next day Reichmann did not fly and I won again, enormously costly. Others are small, less expensive, light, ultra­ exceeding the Australian record for the 500 km triangle. They were light, and foot-launched hang gliders. At the same time, markets exciting years. have become more competitive. There has been no great increase in By the year 2000, things had changed almost as much again. By the numbers of sailplane pilots, even some decline. Established this time there were advanced carbon fibre sailplanes over 26 me­ manufacturers have had difficulties. Some long-established firms tres span with winglets, retractable motors and data loggers. The gave up glider production during the decades covered here. In fu­ nine-year old boy, still lurking within myself, remains totally fasci­ ture there will be more changes, diversifications, mergers, and pos­ nated and astonished. sibly closures. There will be another story to tell and another au­ Yet the memory and rapture of the early years do not fade. In thor to tell it, in a few more years. 1966 I suggested that there should be a special class in soaring for old-time sailplanes. 1 Some six years later, inspired by Christopher Wills, the first Vintage Glider Rally was held at Husbands Bosworth in England. I was not there and had no part in the organisation but

i - 'Sailplane and Gliding', December 1966 p. 466 • 9 INTRODUCTION - A GENERAL SURVEY

The direction of development pilots could choose their own goals.3 The achieved distance was the To comprehend the ways in which sailplanes developed, why main criterion for scoring, but a large bonus was added for reaching they have taken the form they have, it is necessary to consider the goal. This presented competing pilots with difficult choices. A how the sport of competitive soaring has changed. Soaring very long distance flight which nevertheless was not quite complet­ Championships are a kind of shop window where the latest wares ed, might score less than a successful, shorter one. Should the cho­ are demonstrated. New types of sailplane, techniques and instru­ sen goal be near, with high chances of reaching it and getting the ments are publicly tested and pushed to their limits under the in­ bonus, or further off, in the hope of scoring exceptionally well by tense conditions of competition. Pilot's reports and technical actually managing to get there? analyses are studied by gliding club members, most whom have It was soon realised by rule makers that distance task and retrieving no aspirations to winning championships but who nonetheless problems could be reduced if courses were directed round one or want to fly the best available sailplanes, if they can afford them, more nominated turning points, 'out and return' or perhaps zigzag and exploit new equipment. fashion along a set line, allowing large distances to be achieved with­ In 1920 the contest-winning pilot was one who could stay air­ out necessarily landing far from home. This raised the problems of borne in a glider for a long time. By 1954 duration records exceeded verifying the turns. This was solved at first by sending observers out 56 hours. It was recognised that, given the right weather condi­ with binoculars early and marooning them for the day at the speci­ tions, duration tests had become only a matter of staying awake. fied points. The idea of using cameras, for pilots to photograph the Something of the same happened with altitude flights. For many turning points, was adopted and became a normal part of competi­ years pilots in contests could score points by gaining height, prov­ tion and badge flying. Competition organisers set up dark rooms for ing their claims with barograph charts. Now climbs to the stratos­ film development, skilled photo-interpreters had to be found. To get phere have been achieved. To exceed these records requires special results out early they often had to work all night. Cameras had to be apparatus. A pressurised sailplane, the 'Alcor' of Robert Lamson, sealed. The photos were often blurred and dim. Cameras could fail, was completed and flown in 1973 2 for research purposes, but pilots could point their lenses a few degrees off, missing the aiming height gains were long ago eliminated from contest scoring. point entirely, press the shutter too soon or too late, appearing then The emphasis moved to cross country flying. Pilots would choose to be 'out of sector', even in the wrong county. Brilliant pilots some­ their day, take off as soon as thermals started and fly, usually down­ times lost their points because they were bad photographers. wind, as far as they could, landing sometimes in fading light, often Anomalies arose when, as sometimes happened, a pilot who hundreds of kilometres from base. It was important to soar in weak completed a course in quick time, was scored the same as another lift at the beginning of a flight and at the end, as evening ap­ who took all day to reach exactly the same place. Surely, the proached, floating in the lightest of airs to extend the distance. But faster pilot was the better? The speed task was introduced. Only in the best part of the day, theory showed that much was gained by the achieved average speed would count for scoring. At first, flying fast in the glides. Designers took note. Sailplanes began to ap­ times were taken from take off to touch down. The choice of pear with higher wing loadings to allow greater speeds with mini­ launch time became ever more critical. Too early, when condi­ mal height loss between thermals. To preserve climbing ability, as­ tions were weak, a poor score resulted. The goal might be reached pect ratios increased, wing spans began to stretch. while stronger thermals were still available to the later starters. As sailplanes improved, and pilots began to read the weather more They would make better time. But after taking off too late, ther­ skilfully, the so-called 'free distance' task or 'downwind dash', lost its mals might begin to die before finishing. Before launching, appeal. Political frontiers and natural barriers, areas of inhospitable everyone waited to see how conditions developed, watching the country like dense forests, deserts or the sea coast, often brought most experienced pilots to see what they would decide. Then flights to a premature end. Sometimes in competitions the winning everyone demanded a launch at the same time. An error in the distances were so great that the best pilots could not get back in time choice of take off time could sometimes be retrieved. It was al­ to fly again the next day. To retrieve aircraft and pilot, a long and lowed, at this stage of development, for a pilot to land short of costly journey by road (or occasionally by aero-tow) was required. the goal, and rush back to start again. But this became dangerous Goal flights to pre-declared destinations made the distance task on the roads as trailer crews rushed madly back and forth. Glid­ more interesting and practical. In some contests during this period, ers might be de-rigged and rigged again carelessly in desperate hurry. Eventually, for safety, such 'relights' after outlandings, 2 - See 'Soaring', November 1973 and OSTIV Publication XIII, 1974. were forbidden in contests. But designers at least recognised that 3-The 'pilot choice' of goal was still permitted in minor regional and some National Championships in the late sixties, although it had been eliminated from World Championships long before. sailplanes should be easily taken apart and put together again. INTRODUCTION

It became accepted at last that all competitions would be, essen­ Starting gates tially, closed circuit races, with controlled starts to equalise every­ one's chances. It became necessary to lay out start and finish lines Even with perfect organisation and plenty of tugs it might take at and a proper system of timekeeping. An acceptable start required least an hour to get everyone off. Some of those airborne early the sailplane to go through an invisible aerial gate, one kilometre would use the time to explore conditions on track but must return wide with a 'limbo 1 bar at 1000 metres. Elaborate sighting devices to make a timed start. Shortly before the 'gate' opened, the were set up. Observers using these were required to identify and sailplanes would gather overhead, rather like swarms of bees round time each sailplane going through, confirming (or not) a 'good a honey pot. start' by radio. Crossing too high, or outside the kilometre wide Once the start gate was open all would want to set off at about frame, was not allowed. the same time. Starting early was not advisable because the other More important decisions which, previously, a pilot had to make, pilots would be watching. If the first thermal was a good one, they were now handed to the contest director. A large fleet of competing would all start and race to join, catching up and thus gaining a time sailplanes, perhaps eighty or a hundred, would be waiting. To send advantage. Starting very late, a pilot might be left behind, with no anyone off anyone too soon, before soaring was possible, would be other sailplanes in sight to mark the good thermals. unfair. They would have to land again almost at once and go to the To get below the 'limbo' bar and still retain as much energy and back of the line. Therefore launching should begin only when the height as possible, some pilots dared to exceed the maximum per­ director knew conditions would be at least soarable for the entire mitted speed of their sailplanes, diving through and pulling up fleet. (A 'thermal sniffer' sailplane might be sent up to help with steeply afterwards. This was dangerous. Collisions were likely when this decision.) But in addition, no-one should be allowed to start on scores of other sailplanes were doing the same thing at nearly the task while others were still on the ground waiting for a tow. Those same time. Collisions could happen also when several pilots arrived airborne must wait till the starting gate was officially open, at a together at a turning point, banking steeply to take their pictures. time chosen by the director. For the sailplane designer, all this meant that soaring in weak Gaggling thermals had lost much of its importance. The task setters ensured, as far as possible, that tasks would be flown in the best conditions Under these rules, racing tended to become a matter of great gag­ available, the racing sailplanes would fly only during the good part gles of sailplanes all following the same track, crowding together in of the day. Early and late hours were no longer of interest except for the same thermals, again with considerable danger of collision. A any unfortunates who, for some reason, had to struggle somewhere pilot could pursue one gaggle after another to achieve a good time out on track to stay airborne. without, at any stage, having to consider strategy. Champion pilots The search for the strongest thermals was vitally important. If the found themselves hotly pursued by others riding on their coat tails, first 'lift' encountered was weak, the glide with an efficient sailplane perhaps gaining a few seconds on the 'final glide' at the end. This was good enough to fly on to find a better one. Even a heavy kind of 'sandbagging' became very common. Some contestants ob­ sailplane can climb in a strong thermal. Wing loadings rose further. jected that, in practice, there was only one kind of decision remain­ Water ballast tanks were fitted, their capacity often exceeding the ing for a pilot to make; who should one follow. weight of the pilot. It became necessary to weigh sailplanes on their way out to the launch point, to ensure that no one was loading so The finish line much ballast that the airworthiness of the aircraft was threatened. If conditions unexpectedly began to die the water could be dumped. The finish was checked and timed visually. A large gaggle could ar­ At the start of the period covered in this book, the contest and rive all at once. For the timekeepers, even with brief warnings by ra­ task situation was in flux. In the 1965 World Championships there dio, it was easy to mis-time or miss seeing someone altogether as were six contest days and six tasks, all 86 pilots expected to attempt they crossed the line perhaps just above the ground at very high all. Only one day was 'free distance'. Another day was distance speed. The airfield, entirely empty a few minutes before, would sud­ along a fixed line round three turn points prescribed by the task denly become dangerously overcrowded. A score or more of gliders setters. One day was a race to a distant goal. Two days were closed would be shooting over the finish line, pulling up to perform ab­ circuit races. After this, the closed circuit speed task became almost breviated circuits, jettisoning water ballast, landing, not always universally accepted for all major competitions. neatly on the specified track or in the prescribed direction, rolling, coming to a stop, then being wheeled away by anxious crews dash­ The contest day ing about with cars, ropes or towing bars. During most of the following three decades, a typical contest day Changing the rules followed the pattern described here. At a morning briefing, the set task, usually a triangle or quadrilateral of at least several hundred When cameras with time and data recording on the film became kilometres, would be announced. The entire fleet would be mar­ available, the starting problem was eased to some extent. A pilot shalled and assembled ready for take off. If the weather deteriorat­ could photograph a base point and the time would be taken from ed, the task could be shortened or even cancelled at a late stage. the film. Alternative start points, without affecting the total dis- INTRODUCTION

tance of the task, could be nominated, which gave the fleet more for both contest and record purposes. Further changes and adjust­ room. The limbo bar and start gate were dispensed with. There were ments to the class system are likely. serious efforts, not entirely successful at first and sometimes not The emphasis is always chiefly on the wing span. All else being welcomed, to make tasks more flexible, giving the pilots some equal, a sailplane with a large span and a high aspect ratio, will, in choice of task and turning points, reducing the size of the gaggles straight flight at least, perform better than one otherwise similar but and requiring pilots to make more critical decisions. smaller. In the drawings and descriptions on later pages, the effect of this can be seen clearly. In 1965, eighteen metres was considered nor­ The Global Positioning System mal for the Open Class. As the following pages show, things changed. The 'Eta 1 , flown first in the year 2000, has a span of 30.9 metres. Subject at first to various restraints and limitations, GPS instru­ There are other types with spans between 20 and 26 metres. ments for sailplanes were advertised already in 1991. They were very costly at first. One instrument might cost several thousands of dol­ Class Reinforced Plastics lars. This soon changed. The instruments became reliable, compact, less expensive, and incorporated data logging. Serious experiments In 1965 at South Cerney in England both World Championship class­ with sailplanes began in 1993 in Sweden and by 1995, in the World es were won by pilots flying wooden sailplanes. In the Open Class Jan Championships in New Zealand, every competitor was required to Wroblewski from Poland became World Champion in a Foka 4. This submit a GPS 'black box 1 to the scorers after flying. Not only was a was a fifteen metre span Standard Class glider, with a fixed undercar­ task flight, course and time verified (or not) but points could be cal­ riage, no flaps or other complications. His team mate, Ed Makula, culated too. Everything could be downloaded to a suitable comput­ placed fourth in an identical aircraft. Francois Henry of France won er and stored, a complete record of each flight, locations, heights, the Standard Class in a Siren C30 Edelweiss.4 The Swiss Standard Elfe 5 speeds, all plotted on a map and available for subsequent analysis. and two more Polish Fokas were not far behind in the scores. All Some of the old skills of navigating by map and compass became these were made of wood, although some plastics were used in sand­ almost superfluous. A pilot might complete a long task yet hardly wich skins and for streamlined nose caps, wing tips and fairings. be aware what kind of country lay below. In wave conditions, as They conformed to the Standard Class specification but not to the sometimes in New Zealand, a task could be flown almost all above spirit of the rules which had originally been framed to encourage the cloud without sight of the ground. Gaggling and sandbagging were development of good, inexpensive club sailplanes. The original Ka - not abolished but became less prevalent. The data logger encour­ 6, design prize winner of 1958, remained the best exemplar. ages the introduction of new, more flexible competition tasks in­ The success of the Polish pilots was attributable mainly to their volving much greater degrees of pilot judgment and variety. The team flying. Any disadvantage in sailplane performance was more GPS is not perfect. Instruments and satellites might still sometimes than made up by this highly developed technique. Pilots in the fail. But these changes are generally welcomed. The long term im­ team communicated constantly by radio, doubling or more than plications remain to be discovered. doubling their chances of finding the best thermals in what turned out to be a mediocre English summer. Class wars Second place in the Open Class in 1965 went to Rolf Spa'nig in the Darmstadt D - 36. This German sailplane was built from glass- At the beginning of the period covered in this book, there were two fibre-reinforced plastic (GRP). Sandwich glasscloth skins were classes of competition sailplanes. In the 'Open Class' any kind of stiffened with balsawood filling. Spars were glassfibre rovings motorless aircraft, of whatever size, complexity and cost, was per­ with epoxy resin matrix. There were occasional light internal mitted. The 'Standard Class' was limited to sailplanes of 15 metres wooden frames. The aerodynamic perfection of the external shape or less span, with few complications, no retracting wheels, ballast or was obvious and the performance showed a huge advance. But, as flaps. This simple arrangement soon began to break down. Dissatis­ one technical commentator remarked, the structure of the D - 36 faction with the Standard Class specification led to changes which was heavy, expensive and very elastic. At high airspeed the tor- by 1974 produced some undesirable developments. This led to the sional flexibility of the wing caused the ailerons to become rela­ introduction of the 'Fifteen Metre' class, sometimes misleadingly tively ineffective. There had been some tail flutter during the termed the 'Racing Class' (misleading because all sailplanes are flight tests, necessitating a heavy mass balance and, subsequently, flown in races). Standard, Fifteen Metre and Open Classes remained redesign of the tailplane. The epoxy resins might become very in World and National Championships. There was a move to estab­ weak at high temperatures, not perhaps in Europe but in climates lish an 'Eighteen Metre' class. In an attempt to reduce costs, a where sunshine was more constant and intense. The Germans 'World Class One Design' sailplane (the PW - 5) was chosen, after a themselves nicknamed the D - 36 'Gummiflugel' (Rubber wings). design competition. Championships were held for this. 'Club' and The only other glass-plastic sailplane in the contest was the Phoe­ 'Junior' classes have also been recognised internationally. Handi­ bus which placed eighth in Standard Class, a good result but not cap systems allow many types of aircraft to compete on more-or-less enough to astonish anyone. Two Fokas, two Edelweiss, a Dart and equal footing. Special competitions for women pilots are organised and there are acrobatic championships. To this increasingly compli­ 4 - See Volume 2 for the Foka 4 and Edelweiss cated scene, it has become necessary to admit motorised sailplanes, 5 - In this volume, p. 224 INTRODUCTION

even a Ka - 6CR,6 placed higher in the final list. The OSTIV (Or­ remains in service.) All the designers, with computers and wind tun­ ganisation Scientifique Internationale du Vol a Voile) design prize nel test results, were arriving at similar results. As the years passed the was awarded to the Slingsby Dart, a wooden aircraft. apparent similarities increased. Also, because high temperatures un­ Many well-qualified engineers were at first doubtful about the fu­ der strong sunlight are not good for the resins, sailplanes were fin­ ture of plastic structures. Most probably agreed that for the higher ished in reflective white all over, except for occasional pale registra­ performance sailplanes, traditional methods would soon have to be tion letters or numbers, the maker's logos and perhaps one or two abandoned. Aerodynamicists pointed always to the need for more patches of bright colour to aid visibility. To be sure of what one was and more accurate wing contours and more refined tail units and looking at, it became necessary to ask, or peer into the cockpits. fuselage shapes. Even with plastic foam filling to support plywood There were, nonetheless, important differences, not always appar­ skins, progressive drying out of the wood and shrinkage of the ent from outside. Aerodynamic research, especially at Stuttgart, glues affected the aerodynamic form after a few seasons. There was Braunschweig and Delft Universities, showed that sailplane perfor­ constant demand for more airspeed. To achieve the necessary mance could be further improved by introducing new wing profiles. strength, wooden spars were becoming next to impossible for the There were advances in production methods. Balsa wood filling for thinner wings now required. Metal reinforcements began to seem sandwich skins was soon abandoned in favour of various 'hard' necessary. Rather difficult techniques of wood-to-metal bonding, foamed plastics, unaffected by changing humidity. Vacuum bagging outside the experience of most woodworking shops, were required the hand-laid skins in the moulds, heating components in auto­ for this. Wooden gliders were mostly hand-built, glued together claves to cure the resins, became normal practice. Aramid (Kevlar ) piece by piece. This was costly in terms of labour. and especially carbon fibres, only whispered about in 1965, were in­ Plastic sailplanes too required a great deal of handwork in build­ troduced. By 1979 the cost of carbon fibre was not so excessive. Soon ing and temperature control was necessary to cure the resins. Ex­ new designs were produced almost entirely in CRP (Carbon-fibre re­ pensive female moulds, at least for the wings, were essential. To pre­ inforced plastic). Stiffness and strength were achieved with much vent flutter the wings had to be stiff and control surfaces required less weight. New methods of shaping the crucial moulds were intro­ careful mass balancing. The load bearing structures had to contain duced, computer controlled machinery replaced some of the diffi­ much more material than was needed to resist static loads, simply cult and energy consuming handwork, production lines were tidied to stiffen them. Hence GRP sailplanes tended to be heavy. Nor was up and better organised. There were important changes of emphasis it entirely clear that the smooth skins of the glass/plastic wings in the design of cockpits. Attention was, at last, paid to protection of would remain as perfect as they were on leaving the factories. The the pilot in accidents and heavy landings. resins often shrink appreciably as they age. Since the late 'eighties, there have been further aerodynamic re­ Some designers believed that light alloys must be the best way for­ finements. To understand these some technical knowledge is neces­ ward. The necessary techniques and design methods for metal air­ sary and a brief attempt is made below to provide this. craft structures were well understood. At South Cerney there were several outstandingly successful designs in metal, the American Sisu Turbulators and HP 12, the Yugoslavian Meteor, the Russian A - IS.7 They were strong, light, stiff and, given the right experience and tooling, easy Turbulators, usually on the undersides of wings and on tails, slight­ to build. Imperfections of external form, caused by riveting and skin ly in front of the hinged control surfaces, began to appear on joints, could be improved by careful filling and smoothing. Metal fa­ sailplanes from about 1980 onwards. tigue was a known factor and could be allowed for, whereas the rele­ Great improvements in sailplane performance had come from the vant research into fatigue of glass/plastic aircraft remained to be adoption of low drag, 'laminar flow', aerofoil sections, particularly done. No-one knew what the life of a plastic glider might be.8 the NACA '6' series of profiles. In these, if the wing is accurately Nevertheless in 1968 at Leszno in Poland, there were thirty-one made, smooth and clean, the pressure change across the chord is as GRP (Glassfibre reinforced plastic) gliders in a field of 100 and the shown in Figure 1. top six places in the Open Class went to the plastics. In 1970 at Mar- The highest pressure on a lifting wing is slightly under the lead­ fa in Texas, among a total of 79 competing sailplanes, there were ing edge. At this 'stagnation point' the flow velocity at the surface only seven wooden and five metal aircraft. In 1972 at Vrsac in Yu­ is effectively zero. From here, on both upper and lower surfaces, goslavia, there were 10 wooden and one metal sailplane, the Italian the velocity of the airflow increases until a minimum pressure Caproni Calif A -15, in a field of 89. By the 1974 Championships in point is reached. If the wing is at a suitable angle of attack, the ac­ Waikerie, Australia, there were no wooden aircraft and only one celeration is less below the wing than above, creating a pressure metal, the Caproni A -21 two seater. difference between the two. The total difference in pressure be­ tween the two surfaces, produces the lifting force. It is important Carbon and Kevlar to note that the flow on both sides speeds up at first after leaving the stagnation point. It was already remarked in 1970 that the new plastic sailplanes, for good aerodynamic reasons, were beginning to resemble one another 6 - The D - 36, Phoebus, Dart 15 and Ka6CR were described in Volume 2 of the present series. 7 - See Volume 2 externally. The D - 36 would not have looked out of place in an Open 8 - Research on fatigue life of CRP sailplane structures was started at Darmstadt and by the Clasflugel Com­ pany in the sixties. It has continued ever since. For a survey see Technical Soaring, Vol 26, No 2, April 2003. Class competition thirty years later. (One of the two examples built Generalising, the metal fittings usually have lower fatigue life than the plastic composite structures. INTRODUCTION

Figure i Figure 3: Laminar separation bubble with turbulent re-attachment

Flow velocity gradients over a cambered NACA 6 profile Mam stream forced to separate Laminar flow on both surfaces as far as th but re-attaches Thickening of boundary layer point of maximum/low velocity aids re-attachment

=-__« turbulent boundary layer Mam stream flow velocitv

Transition point, lower surface

Flow velocity increasing rapidly on both sides The next important steps forward were the result of calculation and research, chiefly by Richard Eppler and Francis X Wortmann, both at Chord % Stagnation point, fow velocity zero. Stuttgart University, with extensive wind tunnel testing by Dieter Al- highest pressure thaus. Figure 1 shows that the velocity gradient behind the mini­ mum point on the NACA '6' profiles, starts abruptly. The pressure Angle of attack increases thence linearly to the trailing edge. The new profiles, by Eppler and Wortmann, were computed so that the onset of the in­ After passing the minimum pressure point the flow velocity begins evitable deceleration was much more gradual. Air is a fluid and all to fall again with the associated rise in pressure. In the forward fluids have a certain viscosity or 'stickiness'. In air, viscosity is rela­ zone on an accurately made and clean low drag wing, where pres­ tively small but it exists and is influential at airspeeds applying to sure is falling, the boundary layer close to the skin remains lami­ sailplanes. This allows the laminar boundary layer to persist, in a nar. In laminar flow layers of air slide smoothly over one another delicate state, for a small but useful distance aft of the minimum with little friction. After the minimum pressure point, the bound­ pressure point. A transition zone, rather than a definite point, can be ary layer on such a profile quickly becomes turbulent. A turbulent established. Transition does eventually take place before the trailing boundary layer has a scrubbing action on the wing, with high edge is reached (Figure 2) but there is a saving in total drag. drag. The NACA '6' series profiles achieved low drag because lami­ With such profiles accuracy of the surfaces is of even greater im­ nar flow was preserved over much of the forward part of the wing. portance. It is in this region of the highly sensitive boundary layer The second digit of the profile name indicates, in tenths of the that many older sailplanes had ripples or humps where main wing chord, where the minimum pressure point should be, for example spars lay just beneath the skin. The introduction of GRP structures at 30% (NACA 633 - 618, Ka 6), 50% ( NACA 652-515, Zefir 2). Be­ enabled full advantage to be taken of the new principles. Another cause of imperfections in the wing skins, and because of the accu­ problem then arose. In flight, especially when low down and flying mulation, in flight, of crushed insects on the leading edges, the de­ fast, sailplane wings, like car windscreens, pick up thousands of in­ signed figure was rarely or never reached but there was a great im­ sect bodies, crushed by impact. Devices, called 'bug wipers', to provement in drag compared with the old Gottingen and NACA clean these off in flight have been developed but are not wholly four digit profiles. successful. Attention has been paid to designing wing profiles that will pick up fewer 'bugs'

Figure 2 The detail of how a laminar boundary becomes turbulent has been the subject of much research, especially at Braunschweig and Delft Flow velocity gradients over a modern sailplane profile Universities. Often, transition is associated with a separation 'bubble' In laminar flow the layer of air nearest to the skin of the wing is Laminar f\ow on both surfaces as jar as the Gradual deceleration,of transition point unstable boundary layer scarcely moving, relatively to the surface. This is part of the reason for the low drag. When this very slow moving air begins to meet adverse pressure gradients, it comes soon to a standstill. Thus halted, it forms a Main stream flow velocity barrier to the flow immediately behind it. The general stream cannot Lower surface

Figure 4: Turbulator forces transition without separation Flow velocity I ' Flow velocity increasing rapidly 3 decreasing on both sides I on both sides

Stagnation point, flow velocity zero, highest pressure

boundary laye> Angle of attack Turbulator INTRODUCTION

stand still. Air cannot behave like cars in a traffic jam. The flow rides Figure 5: The wing tip vorte up over the blockage and separates from the wing surface. Such a dis­ turbance breaks up the smooth laminae. The boundary layer becomes turbulent and considerably thicker. All being well, after a short leap the flow returns to the skin, albeit with the usual scrubbing, high drag action of turbulent flow. Just behind the separation point there forms a small zone of stagnant air, not moving with the general flow but forming a small 'bubble' which, although having no true skin, has its own internal sluggish circulation. The separation bubble behaves like High pressu a small air brake, increasing the drag (Figure 3). If the boundary layer has already made normal transition to turbu­ lence, no laminar separation bubble will form. On a sailplane wing, the worst effect of the separation bubble can be avoided by 'trigger­ ing' transition just before the lowest lamina comes to a halt. This can be achieved by adding a turbulator. (Figure 4. Some of the earliest work on turbulators was done for model aircraft by F.W.Schmidt in the late 1930s 9. Model wings suffer much more from laminar separa­ winglet to a wing tip yields a worthwhile improvement. Viewed tion than full scale sailplanes, because the chord may be smaller than from the front, the vortex of the left or port wing tip of an aero­ the entire extent of the bubble. The boundary layer never re-attaches. plane or glider, in normal flight, rotates anti-clockwise. A well de­ Laminar separation is then effectively a complete stall of the wing.) signed winglet deflects the flow above the wing slightly outwards, The most common type of turbulator is zig-zag tape glued on to the tending to reverse the rotation. The winglet is cambered and set at wing or tail surface at the required locations. such angles to the flow in the main vortex that it develops the re­ On wings the turbulator tape is usually on the undersurface quired action. The air above the wing, tending to move inwards, about 60 or 70% of the chord, any pneumatic pinholes just ahead passes round the cambered winglet and leaves the trailing edge in a of any control surface hinge line. Pneumatic turbulators blow air direction against the main vortex flow (Figure 7). out of the wing at critical points through lines of pin holes in the The vortex system as a whole is not totally removed. The winglet skin. The air is supplied by small intakes at points of high pressure. itself is a lifting surface and has its own tip vortex. Because it is in There is a slight penalty but this is more than offset by the avoid­ the airflow, it also creates surface and pressure drag like any other ance of the bubble separation. part of the aircraft. But the total vortex system is more diffuse and less energy is lost. Wing tips and Winglets Sailplane designers did not immediately adopt the winglet after Whitcomb's work was published in 1976, partly because the drag For any sailplane, soaring in a thermal or other upcurrent, more saving applies chiefly at high angles of attack and low airspeeds. than 70% of the total drag comes from the wing tip vortices. A tip vortex is formed on a lifting wing because of the difference in pres­ Figure 6: Wing tip shapes sure between the two surfaces. Instead of moving directly from leading edge to trailing edge, the flow is distorted, that on the high pressure side diverting out and up, and that on the low pressure side inclining inwards. A vortex forms and trails off behind the wing. The loss of energy is very great, especially when the wing is Old style operating at a high angle of attack, as in slow flight (Figure 5). Low pressure There were many attempts to reduce the very serious drag of tip vortices. Placing large flat plates at the tip, to straighten the air flow, High pressun has little effect unless the plates are impossibly large. Adding streamlined tip bodies is unprofitable, barely affecting the vortex, yet adding the surface friction and pressure drag of the body itself The Horner tip to the total. Curving the tip down to check the outward flow from underneath, has little effect. The most hopeful results came from Effective span the slightly upswept wing tips devised by Sigmund Horner. A great Low pressure many sailplanes have Horner tips. It is also calculated that a wing Theoretical basis

tip should be slightly swept back (Figure 6). High pressure In 1976 R T Whitcomb, a NASA aerodynamicist, published results showing that the addition of a very carefully shaped cambered

9 - Aerodynamic des Flugmodells, 1942, later editions available.

10 INTRODUCTION

cal form of dihedral. Many of the large 'Open Class' sailplanes ap­ Figure 7: Winglets proximate this in flight because the wings bend upwards under load. Camber inwards In the smaller fifteen metre classes the wings bend less. It is almost impossible to build a curved wing, but slight polyhedral may be in­ troduced. Again, as with winglets, any improvement in soaring per­ formance is hard to demonstrate but the additional dihedral has no­ ticeable, and usually favourable, effects on stability and handling.

High pressure Performance testing front elevation Sailplane designers invariably make estimates and publish polar Flow defection by winglet curves. There are always some imponderables in the equations and such estimates have usually proved somewhat optimistic. For these reasons performance curves were not given in the previous volumes of this series. Accurate tests in flight were carried out on only a few early sailplanes before the Second World War, notably by the DPS, and a EGA test group measured polar curves of a handful of sailplanes in the early 'sixties. 10 Since then, led by Hans Zacher of the German Aerospace Centre (DFVLR), Paul Bikle and the Dallas group of Dick Johnson in the USA, many more systematic performance tests have At high speed, gliding fast between thermals, the tip vortex drag been made. Where possible, the resulting published polars are in­ is a much smaller proportion of the whole and winglets add to cluded on the drawings in the present work, to a constant scale for the general parasitic drag. Research by students at Braunschweig, ease of comparison. Flight testing of sailplanes is a notoriously dif­ on a typical 15 metre sailplane, suggested that to achieve the ficult enterprise. Small variations in the air mass where the flights greatest reduction possible of vortex drag required winglets about take place affect the results. Pilots flying the tests differ in tech­ one metre tall. Such an extension created too much drag at high nique. There are small differences between individual sailplanes, speeds. Large winglets also increase the loads on the mainplane, even coming from the same moulds. There is a degree of statistical adding considerably to bending and twisting moments and en­ 'scatter' in all the results. Too much faith should not be placed on couraging flutter. the resulting figures. It was subsequently found that relatively small winglets, if cor­ rectly placed, cambered and set, are effective in reducing vortex Outboard motors drag and do not measurably affect the high speed glide. Most sailplanes since 1990 have been offered with winglets as options. In More and more sailplanes appear with self-launching or self-re­ addition, older sailplanes have been retrospectively modified by trieving capacity. The idea of fitting a small engine to a glider is adding winglets. An example is the Standard Libelle. almost as old as human flight itself; the Wright Brothers were the A small point about winglets is that they should be arranged so first to do it successfully. The first serious rally for motor that, when the sailplane wing is bending upwards in flight, the in­ sailplanes was held in 1959, with rather limited success. It was ward force produced is horizontal. For this reason winglets are usu­ fair to say at that time that a glider with a motor was neither a ally set at slightly outward tilt when the sailplane is at rest and in very good soaring aircraft nor a very good aeroplane. But im­ this position may slightly exceed the nominal wing span. Turbula- provements in the sailplanes themselves and fully retractable tors are also often fitted on winglets. power units, changed this. Most sailplanes produced in 2000, if The performance improvement in flight is not always apparent to not all, were available with fully retractable propulsion systems, the pilot. Winglets do not instantly yield vast improvements in rate 'outboard' motors in the same sense as a yacht may have a small of climb when soaring. The gains are small. Where their value does motor to get out of the harbour or return to port after sailing. become immediately clear, is in aileron control at low airspeeds. Powered sailplanes became well recognised and may set up their The winglet improves the airflow over the outer wing so that the own class records. They are also allowed to compete, without ailerons become more effective, especially during the early stages of their motors, in championships against 'pure' sailplanes. At a launching and after landing. time when most sailplanes are expected to carry large amounts of water ballast nearly all the time in flight, the weight of a motor is Polyhedral of little significance. Once retracted, the glide performance is the same. The introduction of electric and even solar power opens Further research and calculation by Clarence D Cone in the USA and another promising line of development. Richard Eppler in Germany, has shown that vortex drag can be re­ duced if the wing is curved upwards to produce a more or less ellipti­ 10 - Deutsche Forschungsanstalt fur Segelflug, British Gliding Association

11 Plywood skin Class- plastic moulding

Root wing section Wortmann FX 61 -184

Wing section at inner end of aileron Wortmann FX 61

Wing tip section Wortmann FX6o - 126

Mass empty 400 kg In flight 590 kg Wing area 16.2 sq m Aspect ratio 19.3 Wing loading 36.4 kg/sq m

Schneider ES 65 Platypus 1984

4OO AUSTRALIA AUSTRALIA

Modelled largely on the British Gliding Association, the Gliding Fed­ eration of Australia (GFA), under official delegation, controls almost every aspect of administration of the soaring movement. Recognis­ ing that this relieves the government of much expense the Federa­ tion is partly subsidised but there are no funds whatever allocated to the support of research, design activity or production of sailplanes. The GFA can lend moral and verbal support to any project it favours but cannot distribute funds, place advanced orders, or promote par­ ticular design groups or companies. Professional sailplane manufac­ ture has always depended on private companies. Only one of these survived for any length of time, Edmund Schneider Pty. No sailplanes have been built by that firm since 1982. There has always The Platypus cockpit canopy in the open position been a good deal of amateur building, using imported plans and kits. Some highly original design work never moved beyond the trading undercarriage and tail braking parachute. There was nothing drawing board. Several very promising ventures, such as an ad­ anywhere comparable at that time, except the all-metal Caproni A - 21 vanced tailless sailplane by John Buchanan, despite a great deal of Calif, which was much more expensive. Schneider hoped for some ex­ work, did not in the end produce even a flying prototype. ports as well as challenging imported, tandem seat, aircraft in the local market. He envisaged that after testing, the wing would be made in Schneider ES 65 Platypus GRP for production. Only lukewarm interest in the proposed ES 64 was expressed by the gliding clubs and, because the plastic materials The firm of Edmund Schneider was founded in 1928 at Grunau in were unfamiliar to the airworthiness authorities, it seemed likely there Silesia. Unable to continue after the region was allocated to Poland would be difficulties with flight testing a prototype. Schneider became at the end of World War 2, Edmund and his sons emigrated and in discouraged. Financial support was not forthcoming and work ceased. 1952 established a sailplane factory in the State of South Australia After a hiatus of several years, during which some partly-built near Adelaide. Production of a series of successful designs followed, components languished in storage, Schneider decided in 1983 after the ES - 60 and 60B series remaining in production till 1970. n all to go ahead to complete a prototype as a private venture, hoping Harry Schneider, now head of the firm and the only designer, for a that when it was flying, orders would come. Changes in the Aus­ few years acted chiefly as agent for the importation and servicing of tralian airworthiness rules had made testing a new prototype easier. sailplanes from Europe. However, he felt there was a need, in Australia Rudi Geismaier, a graduate engineer from Munich, came to work and elsewhere, for a good two-seater with side by side seating, for ad­ for the small company. Much re-design and re-thinking followed. vanced training and cross country flying. He began preliminary work The more expensive items, like the retracting wheel and tail para­ on a new design, the ES 64, intending to use the wooden wings of the chute, were abandoned, but the basic idea of a modern, low drag ES 60 for the prototype, but with a GRP fuselage. There would be a re- fuselage with side by side seating was retained. A nose-wheel was built in, with a well-faired main landing wheel and hydraulic brake, slightly behind the laden balance point. The extended ES 60 wing was used, with the prospect of plastic moulding later, as before. The tail was GRP with carbon fibre in the elevator to reduce its mass. The completed ES 65, now called 'Platypus', was first flown at Gawler in August 1984. It was generally considered very impressive, handling well and performing fully up to expectations when flown comparatively against a locally-based Grob Twin Astir. There were ambitious plans to make the transition to GRP and put the ES 65 into production. Schneider himself could not undertake such a ven­ ture without very substantial backing. He proposed that the Gliding Federation of Australia should undertake control of the entire pro­ ject, development and production. The GFA, however, was (and re­ mains) only a representative body of delegates elected by clubs and state associations. Tentative plans were made by the Federation Council for the foundation of an independent consortium. A refer­ endum among club members was staged to discover if there was suf-

The Platypus preparing for its first flight 11 - See Volume 2, p. 242

13 Entire nose cone slides forward 558 mm for access to cockpit

Fabric covering Classcloth skin on balsa Classcloth skin on PVC foam Plywood skin Metal skin

MOBA2C wing section Original flaps Wortmann FX 67 - K - 150 not tapered, (Flap 15%) modified slightly no spoilers for extension to flaps

Tapered flaps and spoilers added

Sections through cockpit area Not to scale CRP - plywood sandwich ribs with plastic foam between Top hinge

Metal box spar

Typical wing cross section

Three piece wing rigging joint

MOBA 2 2C Mass empty, kg 266 In flight, kg 361 Wing area, sq m 9.0 Aspect ratio 24.74 Wing loading, kg/sq m 40.1 Centre of Gravity limits 200 - 244 mm aft of root leading edge

Sunderland MOBA 2 1980

Drawn by Martin Simons 2003 © from information supplied by Gary Sunderland AUSTRALIA

ficient interest to launch this scheme. A levy was proposed, and shares in the proposed manufacturing company were offered. Noth­ ing like the required funds was found. More time passed and noth­ ing satisfactory emerged. In 1987, despite touring the country for display purposes and allowing many pilots to fly the Platypus, it be­ came clear that the ES 65 would never enter production. There was some slight expression of interest in licence production in Europe, but this, too, faded. Harry Schneider by now was expecting soon to retire from business. The Platypus was offered for sale as it stood and was bought at last by members of the Beaufort Gliding Club, based at Bacchus Marsh north of Melbourne. At the time of publication it remains there, popular with pilots and giving very good service. (Thanks to Harry Schneider and Alan Patching Above: Gary Sunderland's Moba 2 showing the sliding nose cone partly open for assistance with this article.) Below: The cockpit and instrument panel of the Moba

Sunderland MOBA 2 rails and rollers. When closed, nothing disturbed the airflow over the fuselage as far back as the wing root. The cone was easily removed, al­ Gary Sunderland, an aircraft engineer, had a long-standing ambition lowing easy access to all the cockpit controls and instruments for to design and build his own sailplane, to compete in and even win maintenance. 12 Instruments and controls, the pilot's seat and the re­ the Australian National Gliding Championships in it. It would be, he tracting main wheel, were carried on a substantial metal box structure. said, with tongue in cheek, "My Own Bloody Aircraft" The acronym, The cockpit was small and narrow, too small, Sunderland admitted, MOBA, stuck. As a pilot Sunderland already knew the Libelle H - 301, for pilots much larger than himself. The main control column was and hoped to improve on this or at least equal it, but with a sailplane mounted on the right side, instead of centrally. This original feature that could be assembled easily at home without expensive moulds, allowed even more space to be saved by conducting all control drives jigs, and tooling. After preliminary studies, he began work on the down the cockpit sides, below shoulder height. Moba 2. This was to be a 15 metre span sailplane but with a retracting Substantial vertical frames supported the wing. The rear fuselage main wheel and landing flaps rather than air brakes. It would not, was a built up metal tube of oval section with flat panels above and therefore, conform to the prevailing Standard Class specification. Pre­ below, for simplicity in assembly. The vertical tail was metal with a liminary general arrangement drawings were completed early in 1970 fabric covered rudder, the tailplane metal but the elevator in wood, and some metalwork was done to establish feasible methods. skinned with plywood for stiffness. The main load bearing structures were in light alloy, but the outer The wing was in three pieces, a rectangular centre section carry­ form of both wing and fuselage were in glasscloth, supported by plas­ ing the flaps, with tapered outer panels and metal-skinned ailerons. tic foam. A particularly original idea was the nose cone. This was a shell of glass cloth and balsawood, with the transparent canopy in one 12 - Sunderland's removable nose cone was mentioned by the author in an article published in a model flying magazine in 1980 The idea was adopted by the Australian International Team for the World Championships piece. To give access to the cockpit the entire cone moved forward on in the F3B category. It was subsequently very widely adopted for model sailplanes.

15 BRAZIL

There was a large, rectangular-section main box spar. Accurately cut marine plywood ribs were fitted around the spar, bolted to it at 610 BRAZIL mm (24 inch) intervals. Large blocks of urethane foam were glued between the ribs, cut and sanded to shape. The ribs acted as tem­ Gliding in Brazil has never had a very large following but there has plates for this. After final truing up and sanding, the glasscloth skin been some government support. This has been irregular and not an was added. unmixed blessing. When government funds and bureaucracy are in­ In August 1970 the magazine, Australian Gliding, 13 announced a volved, there also come politics, red tape, and the possibility of un­ design competition. The intention was to encourage the develop­ due influence from pressure groups. Much of the country is very dif­ ment of small, inexpensive cross-country and contest sailplanes ca­ ficult for cross country soaring, and the small community of glider pable of being built by amateurs. Nothing was stipulated about ma­ pilots has always faced severe difficulties. Clubs and private owners terials but the span was limited to 13 metres. The performance was have relied to a large extent on imported aircraft, but these are often to be as good as possible, with the required simple structure. En­ prohibitively expensive. All attempts to establish a local sailplane de­ trants were required to submit their designs on paper with the nec­ sign and manufacture industry failed in the long run. Nevertheless essary stressing justification, performance estimates and details of there have been some Brazilian sailplane designs. One was the Stan­ construction methods. Part of the prize was to be the building of a dard Class IPD Urupema, designed in 1964 by student engineers at prototype by one of the sponsor organisations. After successful test­ the Centre de Estudos Aeronauticos of the University of Minais ing there was the prospect of marketing plans and kits. Gerais. In appearance the Urupema was likened to a Foka 4 but the Sunderland entered the design competition, which was to be structure was different. The skins were of sandwich type with honey­ judged at the end of the following year. His entry was the MOBA comb paper cores. Few other details have been preserved. One com­ 2B, the span cut to the specified thirteen metres. peted in the World Championships in 1968 and two in 70, but the pi­ Entries, many of them very promising, were received from all lots were not experienced in contest flying. Although not disgraced, over the world. In 1972 the Moba 2B was one of two judged to be they did not place highly. It is said that twenty of the Urupema were outstanding, the other being a design in metal by Imre' Bano in built by the leading Brazilian aircraft manufacturing firm, Embraer. Hungary. 14 Unfortunately, after long argument, the judging com­ mittee could not agree on the final award. The competition ended CB - 2 Minuano in fiasco. The prize was never awarded and no prototype was built. Sunderland nonetheless persevered with his fifteen metre design. The Minuano (South-west wind), reputedly the best sailplane ever Before the 1974 World Championships, which were to be held at produced in Brazil, was designed by Professor Claudio Barros of the Waikerie in South Australia, the Standard Class specification was Centre de Estudos Aeronauticos at the University of Minais Gerais. changed. To Sunderland's delight, flaps and retracting wheels were It was Baros' second sailplane design, the first being the CEA - 101 to be permitted and the Moba 2C would now conform. He hoped it CB - 1 Gaivota (Gull). The Minuano was built in the University would be possible to get the aircraft finished in time for an Aus­ workshops during the period 1970 - 74. It employed the latest wing tralian pilot to fly it in the 1974 contest. profiles available from FX Wortmann with a high aspect ratio, three In the event, there was not enough spare time available. Con­ piece wing mounted high on the fuselage. The wing spars were of struction of the sailplane took six years. Moba 2C did not complete light alloy, cleaned and etched for gluing with epoxy resin glue. test flying until 1980, after which it was granted a certificate of air­ Ribs, spaced at half-metre intervals, were cut from a sandwich mate­ worthiness. It handled well, although even with the flaps fully rial of Brazilian pine plywood outer layers with balsa filling. The down for landing, Sunderland found it advisable to add spoilers and increase the flap chord at the root. The result was the Moba 2D. Although by the time the sailplane flew it was considered out of date it achieved the performance expected. In competition it climbed in thermals with larger 'Open Class' sailplanes although, as expected, it did not glide so well as they at high speeds. Unfortunately, after some time the urethane foam began to change, expanding enough between the ribs to spoil the wing con­ tours. Much effort was required to restore the correct form. This in­ volved stripping the skin off the wing, sanding and filling the foam to contour, re-skinning and re-painting. After this the Moba 2 was flown again but, having proved his point to his own satisfaction, Sunderland did not persevere with the design. When it was retired from flying, Moba 2 was more or less abandoned. (Thanks to Gary Sunderland for assistance with this article.)

13 - The Journal of the Gliding Federation of Australia, edited at this period by the author. The Urubu two seater. Only the prototype was built but it remains in service at Sao 14 - Another Hungarian entrant, Kesselyak Mihaly, submitted a design which had some features similar to his KM • 400, see page 171 below. The judges thought it too advanced and difficult for amateur builders. Jose dos Campos.

16 yooo

Plywood skin Plywood - plastic honeycomb

Root wing profile Wortmann FX 61 -163

Flap down 90 degrees for air brakes

Skins: Plywood sandwich with cellulose acetate honeycomb. Ribs: plywood balsa sandwich Wing profile Wortmann FX 61 -163

Mass empty 214 kg In flight 304 kg Wing area 10.2 sq m Aspect ratio 22.05 Wing loading 29.82 kg/sq m

Tip profile Minuano Wortmann FX 60 -126 1974 Drawn by Martin Simons 2003 © from information supplied by Claudio Barros and Paulo Iscold The third of the series, 'Sailplanes' brings the story to the end of the 2Oth Century. Plastic structures became orthodox. Glass was supplemented with carbon and aramid fibres as reinforcing materials. The improved strength and accuracy of structures allowed advantage to be taken of new wing profiles. Retracting motors became more acceptable.

Pilots, modellers and aviation enthusiasts will find descriptions, pictures and excellent scale drawings showing most successfully designs, and some not so successful such as tailless and variable geometry sailplanes, and some less expensive from the flourishing homebuilding scene in the USA and Australia.

Champion pilots have showed how the new aircraft should be exploited. Records for distance and speeds around closed circuits were broken time and again by some of these outstanding sailplanes. Many of them are still available and it is useful to have this background information.

A glimpse of the future?

One example of a true solar-powered, self-launching sailplane is shown on this back cover. A fuller description is within. 6

ISBN 3-saoaa36-1-7 The Wally Kahn/British Gliding Association eBook Library is unable to obtain copyright approval to provide the reader with the complete eBook.

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